Baling machine with air spring means for maintaining apron tension

ABSTRACT

In a roll baling machine having an apron movable in suitable manner to form roll bales of crop material, air springs are used to maintain tension in the apron. The air springs each include an air bag and a piston. The air pressure in the air bags is adjustable in order to adjust the tension in the apron.

BACKGROUND OF THE INVENTION

This invention relates generally to baling machines typically referredto as "round balers" which form cylindrical roll bales of crop material.

In a conventional type of roll baling machine such as shown in U.S. Pat.No. 3,901,007, the upper apron moves from a starting position to a finalposition during formation of a roll bale in an expandable bale chamber.This movement of the upper apron is controlled by a mechanism thatincludes a rotatable arm assembly and extension coil springs. The armassembly helps support the upper apron and rotates from a first positionto a second position to allow the movement of the upper apron from thestarting position to the final position as a bale is formed. Theextension coil springs urge the arm assembly toward the first positionwhile resisting movement thereof toward the second position. Thismaintains tension in the upper apron.

It is desirable for the tension in the upper apron to gradually increaseduring the initial and final stages of the bale forming process and toremain substantially constant during the intermediate stage of the baleforming process. This effectively controls the density of a roll baleduring formation. In the baling machine shown in the above-mentionedpatent, such variation in the upper apron tension is achieved byemploying a rather complex arrangement of cam plates, cables and pulleysin combination with the extension coil springs which exert a constantforce.

It is also desirable for the tension in the upper apron to be quicklyand easily released for servicing the machine. In the baling machineshown in the above-mentioned patent, it is a difficult and lengthyprocedure to release the tension in the upper apron because of thearrangement of cam plates, cables and pulleys used with the extensioncoil springs. Furthermore, these extension coil springs are difficult toremove from the machine because they are very bulky and heavy.

SUMMARY OF THE INVENTION

The present invention provides a roll baling machine having apron meansfor forming a roll bale of crop material and air spring means formaintaining tension in the apron means. The air spring means operates tocontrol the tension maintained in the apron means during bale formationin order to control the density of a roll bale as it is formed.

In the preferred embodiment of the invention, the air spring meansincludes an air bag for containing air under pressure and a pistonmovable into the air bag to decrease the volume therein and increase theair pressure therein acting on the piston. The air bag and the pistonare formed in a manner which controls the force exerted by the airspring means. The tension in the apron means may be released by simplyreducing the air pressure in the air bag to a predetermined level. Theair pressure in the air bag is adjustable in order to adjust the tensionin the apron means. The piston preferably has a tapered portion formedso that the effective area of the piston acted upon by the air pressurein the air bag decreases during bale formation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a roll baling machine embodying thepresent invention taken when the machine is empty and the apron is inits starting position;

FIG. 2 is a side elevational view of the machine shown in FIG. 1 when abale has been formed in the machine and the apron is in its finalposition;

FIG. 3 is an enlarged view of a portion of the machine of FIGS. 1 and 2showing the arm assembly and one of the air spring assemblies;

FIG. 4 is an enlarged sectional view taken along the lines 4--4 of FIG.3;

FIG. 5 is an enlarged sectional view taken along the lines 5--5 of FIG.3;

FIG. 6 is an enlarged plan view of the arm assembly taken along thelines 6--6 of FIG. 3;

FIG. 7 is a view similar to FIG. 3 with the arm assembly and the airspring assembly removed;

FIG. 8 is an enlarged side view of one of the air spring assemblies;

FIG. 9 is a side view of the arm assembly of FIG. 6; and

FIG. 10 is a graph comparing bale size and apron tension for the machineof FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the roll baling machine embodying the preferredembodiment of the present invention includes a base frame 10 havingopposite sides each formed generally of frame members 12, 14, 16 rigidlyconnected in a triangular configuration with side plates substantiallycovering the space therebetween. Each side of the base frame 10 includesan upper section, as best seen in FIG. 7, which consists of a framemember 18 rigidly connected to the frame member 16, a bracket 20 rigidlyconnected to frame member 14, and a frame member 22 rigidly connectedbetween the frame member 18 and the bracket 20. A plate 24 is connectedto and covers the space between the frame members 14, 16, 18 and 22. Arear frame 26 is pivotally connected at 28 to the base frame 10 bysuitable bearings. The rear frame 26 has opposite sides each formedgenerally of frame members 30, 32, 34, 36 rigidly connected in asubstantially trapezoidal configuration with side plates substantiallycovering the space therebetween. Other frame members (not shown) extendtransversely of the machine and connect the opposite sides of the baseframe 10 and the opposite sides of the rear frame 26. In FIGS. 1 and 2,the forward end of the machine is to the left and the rearward endthereof is to the right.

The rear frame 26 is pivotally movable from the lower position of FIG. 1to an upper position (not shown) by conventional means such as hydrauliccylinders (not shown) mounted at the sides of the machine and connectedbetween the base frame 10 and the rear frame 26.

An arm assembly 38 is rotatably mounted on the base frame 10 forrotational movement between a forward position shown in FIG. 1 and arearward position shown in FIG. 2. The arm assembly 38, as also shown inFIGS. 6 and 9, includes arms 40 disposed inboard the sides of themachine. Each arm 40 consists of two portions 40a and 40b which arepreferably box-shaped members of rectangular cross-section weldedtogether. The arms 40 are rigidly connected to a cross tube 42 bybracket members 44. Each bracket member 44 includes a pair of flatplates 44a welded at one end to an arm portion 40a and having holes atthe other end for receiving the cross tube 42. The flat plates 44a arewelded to the cross tube 42. Each bracket member 44 also has a flatplate 44b connected between the flat plates 44a. The cross tube 42 isrotatably mounted in bearing members 46 and 48, best seen in FIG. 7,carried by the brackets 20 on the opposite sides of the base frame 10.The arm assembly 38 also includes auxiliary arms 50 disposed outboardthe sides of the machine and rigidly connected to the cross tube 42.Each auxiliary arm 50 consists of a pair of flat plates 50a having holesat one end for receiving the cross tube 42. The flat plates 50a arewelded to the cross tube 42. Braces 52 are connected between the bracketmembers 44 and the auxiliary arms 50.

The arm assembly 38 carries rotatable guide members 54 and 56 on its armportions 40a and 40 b, respectively. The base frame 10 supportsrotatable guide member 58, 60 and cam guide members 62 inboard itsopposite sides. Preferably, the cam guide members 62 are of the knowntype disclosed in U.S. Pat. No. 3,901,007 and designated therein by thenumeral "118". Sprockets 64 are provided inboard the opposite sides ofthe base frame 10 and are fixed on a shaft 66 that is rotatably mountedin suitable bearings on the base frame 10. The rear frame 26 supportsrotatable guide members 68, 70, 72, 74 inboard its opposite sides. Theguide members 74 are carried on brackets 76 projecting from the framemembers 30 of the rear frame 26.

A flexible bale forming apron 78 is movably supported on theaforementioned guide members and sprockets following the path shown inFIG. 1 when the machine is empty. The apron 78 is preferably formed of apair of endless link-type chains 80 connected at spaced intervals bytransverse bars or slats 82 as seen in partial view in FIG. 1. The apronchains 80 extend around and engage the various guide members and thesprockets 64. From the sprockets 64, the apron chains 80 extend upwardlyaround the guide members 58, 54, 60 and 56 in succession to dispose thepart of the apron 78 supported by the arm assembly 38 in a substantiallyS-shaped configuration in side elevation. The guide members 58, 60mounted on the base frame 10 engage the outer surfaces of the apronchains 80, and the guide members 54, 56 carried on the arm assembly 38engage the inner surfaces of the apron chains 80. The apron 78 is of theknown type disclosed in U.S. Pat. No. 3,901,007 and designated thereinby the numeral "82".

A floor roller 84 extends transversely of the machine and is rotatablysupported by brackets 86 on the opposite sides of the base frame 10.Preferably, the floor roller 84 consists of a hollow metal drum with acoating or layer of rubber on its outer surface. When the machine isempty as seen in FIG. 1, the upper surface of the floor roller 84cooperates with the course of the apron 78 that extends upwardly andrearwardly from the guide members 74 over the cam guide members 62 andthen downwardly and forwardly to the sprockets 64 to define anexpandable bale chamber 88 having an initial wedge shape in sideelevation. In this initial wedge shape, the forward end of the balechamber 88 is narrower than the rearward end thereof. A stripper roller90, preferably rubber coated, extends transversely of the machine and isrotatably supported on the opposite sides of the base frame 10. Thestripper roller 90 is positioned at the forward end of the bale chamber88 in close proximity to the apron 78.

A pickup header 92 extends transversely of the machine and is supportedby brackets 94 on the opposite sides of the base frame 10. The pickupheader 92 is preferably of conventional type having a series ofprojecting fingers 96 rotating in the path 98 for engaging and pickingup windrowed crop material. A pair of wheels 100 mounted on the oppositesides of the base frame 10 support the machine. Another pair of wheels102 are mounted to the brackets 94 to provide support primarily for thepickup header 92. A tongue 104 is provided on the forward end of thebase frame 10 for connection to a tractor.

The machine includes drive means (not shown) adapted for connection tothe power take off unit (PTO) of a tractor. Referring to FIG. 1, rotarydriving power will be delivered from the tractor PTO in a manner tocause rotation of the sprockets 64, the floor roller 84, the stripperroller 90, and the pickup header fingers 96 in the same direction 106.Rotation of the sprockets 64 will drive the apron chains 80 therebypropelling the apron 78 around the various guide members in the baseframe 10 and the rear frame 26 in the direction and along the pathindicated. Preferably, the peripheral speed of the floor roller 84should be equal to or slightly higher than the speed of the apron 78.This will tend to keep a roll of crop material toward the rearward endof the machine during formation.

An air spring assembly 110 is connected between the arm assembly 38 andthe base frame 10 at each side of the machine. Each air spring assembly110, as best seen in FIG. 8, includes a generally cylindrical air bag112, formed of resilient material such as rubber, and a generallyfrusto-conical piston 114 attached to the air bag 112 by a plate 116 andbolt 118 arrangement. The plate 116 is sealingly disposed inside one endof the air bag 112, and the bolt 118 extends through the plate 116 andis threaded into the larger end of the piston 114. A T-bar structure 120is connected to the piston 114 by a bolt 122. The T-bar structure 120 isformed of bar members 124 and 126 which are welded together. The barmember 124 is generally rectangular in cross-section and the bar member126 is generally U-shaped in cross-section as seen in FIG. 5. The bolt122 extends through the bar member 124 and is threaded into the smallerend of the piston 114. A bracket 128 is connected to the air bag 112 bya plate 130 and bolt 132 arrangement. The plate 130 is sealinglydisposed inside the other end of the air bag 112 opposite the plate 116,and the bolts 132 extend through the plate 130 and the bracket 128 andthreadedly receive nuts. Tube members 134 extend through holes in thebar member 124 and are welded thereto. Guide rods 136 extend through thetube members 134 and through bearing members 138 mounted on the bracket128 by bolts. The ends of the guide rods 136 extending through the tubemembers 134 threadedly receive nuts 140. The other ends of the guiderods 136 extending through the bearing members 138 are interconnected bya bar member 142 which is attached to the guide rods 136 by bolts 144.

The bar members 126 of the air spring assemblies 110 are pivotallyconnected by pins 146 to the auxiliary arms 50 of the arm assembly 38.The brackets 128 of the air spring assemblies 110 are rigidly connectedalong their edges 128a to the base frame plates 24 by conventional meanssuch as welding. Braces 148 are connected between the brackets 128 andthe base frame plates 24.

As the machine is pulled across a field by a tractor, the pickup headerfingers 96 engage, pickup and deliver windrowed crop material onto theupper surface of the rotating floor roller 84 in the bale chamber 88.The crop material is carried upwardly and then coiled back downwardlyonto itself by the apron 78 which in its starting position of FIG. 1moves upwardly and rearwardly from the guide members 74 over the camguide members 62 and then downwardly and forwardly to the sprockets 64.This movement of the apron 78 in the bale chamber 88 effectively startsthe core of the roll bale. The rotating stripper roller 90 removes cropmaterial from the apron 78 at the forward end of the bale chamber 88 anddelivers it back downwardly into the bale chamber 88. The roll baleincreases in diameter lifting the inner course of the apron 78 thatextends between the guide members 74 and the sprockets 64 off the camguide members 62, and expanding the bale chamber 88 from its initialwedge shape to a substantially circular shape. The expansion of the balechamber 88 results in expansion of the inner course of the apron 78contacting the peripheral surface of the roll bale and movement of theapron 78 toward its final position of FIG. 2. This movement of the apron78 is accomplished by rotation of the arm assembly 38 in a clockwisedirection as viewed in FIG. 1, from its forward position. When the balereaches its maximum diameter, the apron 78 will be in its final positionof FIG. 2 and the arm assembly 38 will have rotated about 65° to itsrearward position shown in FIG. 2.

When the machine is empty, the arm assembly 38 is held in its forwardposition shown in FIG. 1 by the air spring assemblies 110. At thispoint, the air bags 112 each contain air under pressure (for example,between 50 and 60 psi) which acts on the larger ends of the pistons 114attached thereto. Force is applied through the pistons 114 and the T-barstructures 120 to the auxiliary arms 50 of the arm assembly 38 therebyurging the arm assembly 38 toward the forward position of FIG. 1, whileresisting rotation thereof toward the rearward position of FIG. 2. Thismaintains tension in the apron 78 by urging the apron 78 toward itsstarting position of FIG. 1 while resisting movement of the apron 78toward its final position of FIG. 2. The arm assembly 38 is providedwith stop bolts 150 carried by brackets 152 attached to the arms 40. Thestop bolts 150 engage plates 154 attached to the frame members 14 of thebase frame 10 to prevent counterclockwise rotation of the arm assembly38 as viewed in FIG. 1 past the forward position.

As a bale is formed in the bale chamber 88, the arm assembly 38 isrotated from its forward position toward its rearward position shown inFIG. 2. This rotational movement of the arm assembly 38 causes thepistons 114 to be pushed into the air bags 112 decreasing the volume ofthe air bags 112 and further compressing the air therein. The forceexerted through the pistons 114 and the T-bar structures 120 to theauxiliary arms 50 of the arm assembly 38 remains substantially constantduring most of the rotational movement of the arm assembly 38 eventhough the air pressure in the air bags 112 increases. This is becausethe pistons 114 are conically tapered along their portion 114a in amanner which decreases the effective area of the pistons 114 acted uponby the air pressure in the air bags 112 as the pistons 114 penetrate theair bags 112 and increase the air pressure therein. Therefore, thetension in the apron 78 remains substantially constant during theintermediate stage of the bale forming process as generally representedby the line 162-164 in FIG. 10. During the initial and final stages ofthe bale forming process, the tension in the apron 78 graduallyincreases as generally represented by the lines 160-162 and 164-166,respectively, in FIG. 10. This is because the pistons 114 are formedalong their portions 114b and 114c in a manner that increases theeffective area of the pistons 114 acted upon by the air pressure in theair bags 112 as the pistons 114 penetrate the air bags 112, and thusgradually increases the force exerted through the pistons 114 and theT-bar structures 120 to the auxiliary arms 50 of the arm assembly 38.Therefore, the apron 78 effectively controls the density of a roll baleduring formation and a roll bale of particular density is formed. If itis desired to form a bale of higher density, the air pressure in the airbags 112 is adjusted to a higher level (for example, between 70 and 80psi) when the machine is empty and the arm assembly 38 is held in theforward position of FIG. 1. This results in higher tension in the apron78 during bale formation as generally represented by the line170-172-174-176 in FIG. 10, and a higher density bale is formed. If itis desired to form a bale of lower density, the air pressure in the airbags 112 is adjusted to a lower level (for example, between 40 and 50psi) when the machine is empty and the arm assembly 38 is held in theforward position of FIG. 1. This results in lower tension in the apron78 during bale formation as generally represented by the line180-182-184-186 in FIG. 10, and a lower density bale is formed. It hasbeen found that this adjustability of the air pressure in the air bags112 provides a much wider range of apron tension and consequently a muchwider range of bale density than is possible with the baling machinedisclosed in U.S. Pat. No. 3,901,007.

As the pistons 114 are pushed into the air bags 112, the guide rods 136slide through the bearing members 138 mounted on the brackets 128 andthus generally keep the pistons 114 aligned with the air bags 112. Asseen in FIG. 4, the apertures 139 in the bearing members 138 are largerin diameter than the guide rods 136. This permits a slight rockingmovement of the components of the air spring assemblies 110 with theexception of the brackets 128 which are rigidly attached to the baseframe plate 24. With sufficient clearance between the apertures 139 inthe bearing members 138 and the guide rods 136, there is no binding inthe air spring assemblies 110 as the pistons 114 penetrate the air bags112.

When the machine is empty and it is desired to service the variouscomponents such as the apron 78 and its guide members, the air pressurein the air bags 112 is reduced to a level where the force urging the armassembly 38 toward its forward position is overcome by the weight of theapron 78. The apron 78 is then able to pull the arm assembly 38 from itsforward position into its rearward position. This releases the tensionin the apron 78 so that the various components of the machine may beeasily serviced.

The present invention is not limited to use on roll baling machines thatemploy the particular type of apron 78. Accordingly, the presentinvention may be used on roll baling machines employing other types ofaprons such as the well known type of apron formed of a series ofendless flat belts.

The present invention is also not limited to use on roll baling machinesthat employ a roller type of floor. Accordingly, the present inventionmay be used on roll baling machines employing other types of floors suchas the well known conveyor type of floor shown in U.S. Pat. No.3,901,007.

The following claims are intended to cover all modifications andvariations of the preferred embodiments of the invention withoutdeparting from the spirit and scope of the invention.

Having thus described the invention, what is claimed is:
 1. A rollbaling machine comprising:(a) a frame; (b) apron means supported on saidframe defining an expandable bale chamber, and said apron means movingfrom a first position to a second position during formation of a rollbale in said expandable bale chamber; (c) air spring means, connected tosaid apron means, for maintaining tension in said apron means; (d) saidair spring means including an air bag for containing air under pressureand a piston movable into said air bag to decrease the volume thereinand increase the air pressure acting on said piston; and (e) meanssupported on said frame for picking up crop material and for deliveringsaid crop material to said expandable bale chamber.
 2. The roll balingmachine of claim 1, wherein said air spring means operates to vary thetension maintained in said apron means during bale formation in order tocontrol the density of a roll bale as it is formed.
 3. The roll balingmachine of claim 2, wherein:(a) said air spring means operates toincrease the tension in said apron means during the initial and finalstages of bale formation; and (b) said air spring means operates to keepthe tension in said apron means substantially constant during theintermediate stage of bale formation.
 4. The roll baling machine ofclaim 4, wherein said piston comprises:(a) a first portion which isformed so that the effective area of said piston acted upon by the airpressure in said air bag increases during the initial stage of baleformation; (b) a second portion which is formed so that the effectivearea of said piston acted upon by the air pressure in said air bagdecreases during the intermediate stage of bale formation; and (c) athird portion which is formed so that the effective area of said pistonacted upon by the air pressure in said air bag increases during thefinal stage of bale formation.
 5. The roll baling machine of claim 1,further comprising:(a) an arm assembly for supporting said apron means;(b) said arm assembly being rotatable from one position to anotherposition during bale formation as said apron means moves from said firstposition to said second position; and (c) said air spring means urgingsaid arm assembly toward said one position while resisting movement ofsaid arm assembly toward said another position to thereby maintaintension in said apron means.
 6. The roll baling machine of clam 1,wherein said apron means comprises endless flexible members andtransverse members extending between and interconnecting said endlessflexible members.
 7. The roll baling machine of claim 1, wherein thetension in said apron means is released when the air pressure in saidair bag is reduced to a predetermined level.
 8. The roll baling machineof claim 1, wherein:said air spring means normally urges said apronmeans toward said first position while resisting movement of said apronmeans toward said second position in order to maintain tension in saidapron means.
 9. The roll baling machine of claim 1, wherein said air bagand said piston are formed in a manner which causes the force exerted bysaid air spring means to be variable.
 10. The roll baling machine ofclaim 1, wherein the air pressure in said air bag is adjustable in orderto adjust the tension in said apron means.
 11. In a roll baling machinehaving a frame, apron means supported on said frame defining anexpandable bale chamber, said apron means moving from a first positionto a second position during formation of a roll bale in said expandablebale chamber, means supported on said frame for picking up crop materialand for delivering said crop material to said expandable bale chamber,the improvement comprising:(a) air spring means, connected to said apronmeans, for normally urging said apron means toward said first positionwhile resisting movement of said apron means toward said secondposition; and (b) said air spring means including an air bag forcontaining air under pressure and a piston movable into said air bag.12. The roll baling machine of claim 1, wherein said piston has atapered portion formed so that the effective area of said piston actedupon by the air pressure in said air bag decreases during baleformation.
 13. The roll baling machine of claim 1, wherein said air bagis formed of a resilient material.
 14. In a roll baling machine having aframe, apron means supported on said frame defining an expandable balechamber, said apron means moving from a first position to a secondposition during formation of a roll bale in said expandable balechamber, means supported on said frame for picking up crop material andfor delivering said crop material to said expandable bale chamber, theimprovement comprising:air spring means connected to said apron means tomaintain tension in said apron means, said air spring means including anair bag for containing air under pressure and a piston movable into saidair bag.